# x = sec^2 3y differentiate

How do i differentiate x = sec^2 3y?

I dont understand if i'm supposed to be using the chain rule or product rule. I've been looking at answers but i just dont understand it
Original post by TomokoRainMaker
How do i differentiate x = sec^2 3y?

I dont understand if i'm supposed to be using the chain rule or product rule. I've been looking at answers but i just dont understand it

What have you tried?
Original post by Muttley79
What have you tried?

i did
U = 3y du/dx = 3
y = sec^2U dy/dx = ksec^2UtanU

idk if thats even right. thats all i have bc idk what rule to use
Find dx/dy. Then use that to find dy/dx.
(You're on the right track for dx/dy)
Original post by TomokoRainMaker
i did
U = 3y du/dx = 3
y = sec^2U dy/dx = ksec^2UtanU

idk if thats even right. thats all i have bc idk what rule to use

dx/dy = dx/du * du/dy

Can't follow your method.

Which of those can you find?
Original post by Muttley79
dx/dy = dx/du * du/dy

Can't follow your method.

Which of those can you find?

How am i meant to know to put it into the chain rule? Thats what i dont get
Original post by TomokoRainMaker
How am i meant to know to put it into the chain rule? Thats what i dont get

You wrote:

U = 3y [du/dx] that is dU/dy as you have an equation between two variables U and y

y = sec^2U [dy/dx] here you have an equation between y and U, so it'd be dy/dU
(edited 1 month ago)